According to the examination by the inventor of the present invention, the following techniques are known as the control techniques for the conventional data processing systems.
For example, a database system for handling a large amount of data such as a data center adopts such a method that uses a storage system formed separately from its host system to manage data. This storage system is constituted of, for example, a disk array device and the like. The disk array device is constituted by arranging a large number of storage devices in the form of array and is established based on, for example, the redundant arrays of inexpensive disks (RAID). At least one logical volume is set on a physical storage area provided by the storage device group and this logical volume is provided to the host system. The host system is capable of writing or reading data to/from the logical volume by transmitting a predetermined command.
In such a database system, the amount of data managed by the database has been increasing day by day with the development of information society. For this reason, a higher-performance and larger-capacity storage system has been demanded and new storage systems have been developed to meet such a market demand. As a method for introducing a new storage system into a data processing system, for example, there are a method for replacing old storage system with a new storage system so as to constitute the data processing system all based on the new storage system (Published Japanese Translation of PCT Application No. 10-508967) and a method in which the new storage system is added to the data processing system of the old storage system so that the old and new storage systems coexist.